In a nutshell
- According to studies, multivitamins do not make healthy people live longer or protect them from heart disease.1,2
- A supplement makes sense when there is a reason for it: vitamin B12 for vegans, folic acid before and during pregnancy.3,4
- Some vitamins do harm in high doses: beta-carotene raises the risk of lung cancer in people at risk, and too much vitamin B6 damages nerves.2,5
1Multivitamins
Moderate evidence
390,000 people
People who took multivitamins did not live longer than others over up to 27 years of follow-up — their risk of death
even came out 4% higher.1
Expert recommendation
84 studies
A review of 84 studies with 740,000 people: vitamin and mineral supplements brought little or no benefit against
cancer, heart disease and death; the only exception was a small drop in cancer cases with multivitamins.2
The US Preventive Services Task Force (USPSTF) therefore neither recommends nor rejects multivitamins for prevention,
and explicitly recommends against beta-carotene and vitamin E.6
2When a supplement makes sense
Strong evidence
−69%
Folic acid taken around conception lowered the risk of neural tube defects in the baby (such as spina bifida)
by 69%. A dose of 400 µg a day or more was effective.4
Expert recommendation
B12
Vegans need a reliable source of vitamin B12 — fortified foods or a supplement.3
When vitamin D makes sense is covered in a separate article.
3When supplements do harm
Strong evidence
+20%
In randomised trials, beta-carotene raised the risk of lung cancer by 20% and of death from cardiovascular disease
by 10%, mainly in people at high risk of lung cancer, such as smokers.2
EFSA recommendation
12 mg
The European Food Safety Authority set the upper limit for vitamin B6 in adults at 12 mg a day. Higher doses damage
nerves over time (peripheral neuropathy). The limit is mainly at risk of being exceeded by people who regularly take
high-dose B6 supplements.5
Limited evidence also links some supplements to other risks: vitamin A to hip fractures, vitamin E to bleeding in the brain and vitamin C to kidney stones.2
4Vitamin C and colds
Strong evidence
−8%
Regular vitamin C (at least 0.2 g a day) did not prevent colds in ordinary people, it only shortened them — by 8%
in adults and 14% in children. In marathon runners, skiers and soldiers under heavy physical strain, however,
it halved the number of colds.7
5Each vitamin in detail
How much of each vitamin you need, where to find it and how its forms in supplements differ is covered in separate articles: vitamin A, B1 (thiamin), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6, B7 (biotin), B9 (folate), B12, C, D, E, K.
What to take from this
- According to studies, a multivitamin won't add to a healthy person's health — rely on a varied diet.1,2
- Take a supplement for a specific reason: B12 if you are vegan, folic acid if you are planning a pregnancy.3,4
- Add up the doses from all your supplements and watch the upper limits — for vitamin B6 it is 12 mg a day.5
- In ForkRep you log a supplement from its label, and the app adds up vitamins from food and supplements and warns you about the EFSA upper limits.
Sources
Written on , based on studies available at that date. Newer research may change the conclusions.
- Loftfield E. et al. (2024). Multivitamin use and mortality risk in 3 prospective US cohorts. JAMA Netw Open 7:e2418729. doi.org/10.1001/jamanetworkopen.2024.18729
- O'Connor E. A. et al. (2022). Vitamin and mineral supplements for the primary prevention of cardiovascular disease and cancer: updated evidence report and systematic review for the US Preventive Services Task Force. JAMA 327:2334–2347. doi.org/10.1001/jama.2021.15650
- Melina V., Craig W., Levin S. (2016). Position of the Academy of Nutrition and Dietetics: vegetarian diets. J Acad Nutr Diet 116:1970–1980. doi.org/10.1016/j.jand.2016.09.025
- De-Regil L. M. et al. (2015). Effects and safety of periconceptional oral folate supplementation for preventing birth defects. Cochrane Database Syst Rev CD007950. doi.org/10.1002/14651858.CD007950.pub3
- EFSA NDA Panel (2023). Scientific opinion on the tolerable upper intake level for vitamin B6. EFSA Journal 21:e08006. doi.org/10.2903/j.efsa.2023.8006
- US Preventive Services Task Force (2022). Vitamin, mineral, and multivitamin supplementation to prevent cardiovascular disease and cancer: recommendation statement. JAMA 327:2326–2333. doi.org/10.1001/jama.2022.8970
- Hemilä H., Chalker E. (2013). Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev CD000980. doi.org/10.1002/14651858.CD000980.pub4
This is general information and does not replace a doctor. If you are pregnant, ill or taking medicines, talk to a doctor or pharmacist about supplements.